Tube cold rolling mill

ABSTRACT

A tube cold rolling mill with rolls the grooves of which are spirally threaded with a variable helix angle and a housing with a drive ensuring its reciprocal-rolling motion relative to the vertical axis so that the angle formed by the housing guides and the axis of rolling corresponds to the helix angle of the roll groove.

United States Patent Kozhevnikov et al.

14 1 July 22, 1975 TUBE COLD ROLLING MILL Inventors: Sergei NikolaevichKozhevnikov,

Vystavochnaya ulitsa 3, kv. 73, Kiev; Arkady Semenovich Tkachenko,prospekt Gagarina, 63, kv. 22; Eduard Fedorovich Fedorovsky, ulitsaBabushkina, 8/ l2, kv. 5. both of Dnepropetrovsk, all of USSR.

Filed: July 10, 1972 Appl. No.: 270,563

US. Cl 72/214; 72/249 Int. Cl B21b 21/00 Field of Search 72/214, 208,209, 188, 72/221, 198, 189

[56] References Cited UNITED STATES PATENTS 2,780,948 2/1957Fredricksson 72/189 3,308,643 3/1967 Fahrenholz et al. 72/189 X PrimaryExaminer--Milt0n S. Mehr Attorney, Agent, or FirmWaters, Schwartz &Nissen [57] ABSTRACT A tube cold rolling mill with rolls the grooves ofwhich are spirally threaded with a variable helix angle and a housingwith a drive ensuring its reciprocal-rolling motion relative to thevertical axis so that the angle formed by the housing guides and theaxis of rolling corresponds to the helix angle of the roll groove.

2 Claims, 3 Drawing Figures TUBE cou) ROLLING MILL The invention relatesto tube cold rolling mills employed in metallurgy.

Commonly known is a tube cold rolling mill comprising a stationaryhousing for the working stand with rolls, the grooves of which arespirally threaded with a constant helix angle. and a drive with crankmechanism for moving the stand along the housing guides.

The working stand in such rolling mills is displaced at a constant anglerelative to the axis of rolling equal to the lead angle of the rollgroove, which makes it possible, by increasing the number of turns ofthe roll groove spiral, to enlarge the deformation zone of the billetand hence to increase the mill rolling rate.

However, the increase of the number of turns of the roll groove leads toincreasing the length of rolls and to reducing their rigidity whichprevents the quality of product from being improved.

It is an object of this invention to overcome the foregoing difficulty.

The principal object of this invention is to provide a tube cold rollingmill which would improve the quality of product being rolled.

A'further object of this invention is to provide shorter and more rigidrolls for the mill.

These objects are attained in a tube cold rolling mill including aworking stand with rolls, the grooves of which are spirally threaded,and a drive with crank mechanism for moving the stand along the guidesof the housing, wherein, according to the invention, the grooves of theworking rolls are spirally threaded with a variable helix. angle, whilethe housing is made so as to allow for a reciprocal-rolling motionrelative to the vertical axis and is linked with the stand drive in sucha way that the angle formed by the housing quides and the axis ofrolling is equal, at each moment of time, to the helix angle of the rollgroove spiral, and a crosshead is provided, the housing of which ishinged to connecting rods of the stand drive crank mechanism and has acavity accommodating a holder, made to turn relative to the verticalaxis and hinged to the working stand tie rods and having a hole forpassing a billet.

The rolling mill in which the groove of the working rolls is spirallythreaded with a variable helix angle, while the housing is made so as toallow for its reciprocal-rolling motion relative to the vertical axismakes it possible to reduce the length of the working rolls, to increase their rigidity, and consequently, to improve the quality ofproduct being rolled.

Preferably the linkage of the stand with the drive can be made as acrank mechanism, the connecting rod of which is hinged to the housingand crank wheel adapted to interact with the gear of the shaft withfitted-on another gear meshing with the stand drive gear.

Such a linkage of the housing with the stand drive ensures reliable andsynchronous operation of the drive.

The invention will now be explained in greater detail with reference toan embodiment thereof which is represented in the accompanying drawings,wherein:

FIG. 1 is a plan view with details of the rolling mill, according to thepresent invention;

FIG. 2 is a view of the working stand with rolls having the threading ofgroove according to the present inventron;

FIG. 3 is a cross-section on the line IIl-III of FIG. 1.

The rolling mill described in the drawings has a housing I (FIG.1) whichis installed so as to ensure its reciprocal-rolling movement relative tothe vertical axis 2. To this aim the housing 1 is hinged to connectingrod 3 links with a crank wheel 4 which is in mesh with gear 5 rigidlyfitted on a shaft 6. The other end of the shaft 6 has a gear 7 meshingwith a gear 8 of the drive 9. Guides 10 fixed in the housing I serve formoving a working stand 11 having working rolls 12 (FIG. 2) with shapedgroove 13 which is spirally threaded at a variable hclix angle a alongthe groove. The rolls 12 are fitted out with a rack-and-gear drive 14(FIG. I).

A crank mechanism 15 is connected to the drive 9 of the stand and thecrosshead 18 housing. The latter is. in turn, connected to the workingstand II with hinged tie rods 17 through a holder 20.

The crosshead 16 (FIG. 3) consists of a split housing 18, the interiorof which comprises a holder 20, running in bearings 19, which has athrough hole 21 for passing a billet 22. The crosshead 16 is mounted inguides 23 with strips 24 replaced in case of wear.

The rolling mill operates as follows.

The drive 9 reciprocatingly moves the crosshead 16 along guides 23 withthe help of the crank mechanism 15. The holder 20 of the crosshead l6imparts this reciprocating motion to the working stand 11 by means ofthe tie rods 17. At the same time the motion is transmitted through gearwheels 5, 7 and 8 and shaft 6 to the crank wheel 4 and connecting rod 3wherefrom it is further relayed to the housing 1 of the working stand11.

The extreme (dead) positions of the working stand 11 and the crossheadI6 coincide with the extreme (dead) positions of the housing 1. whilethe laws governing the alteration of the angle of turn of the crankmechanism 15 and the crank wheel 4 with the connecting rod 3 areidentical.

We claim:

1. A tube cold rolling mill comprising a stand with rolls having avariable-section groove provided along a spiral line with a variableinclination angle along the groove length; a housing with guides forsaid stand made so as to ensure its reciprocal-rolling motion relativeto the vertical axis; a drive with a crank mechanism for moving thestand along the guides of said housing; a linkage of'said housing withthe drive of said stand made so that the angle formed by the guides ofsaid housing and the axis of rolling is at each moment of time equal tosaid variable inclination angle of the roll groove; a crosshead, thehousing of which is hinged to a crank mechanism of said stand drive andhaving a cavity to accommodate a holder; said holder being disposed insaid cavity of the housing of said crosshead and able to turn relativeto the vertical axis and having a hole for passing a billet and beinghinged with tie rods of said stand.

2. A tube cold rolling mill as in claim I, wherein said linkage of saidhousing with said stand drive is a crank mechanism comprising aconnecting rod connected to said housing, a crank wheel connected tosaid connecting rod, a shaft having a fixedly mounted first gear linkedto said crank wheel, a second gear fixedly mounted on said shaft, and athird gear on said drive of said stand and meshing with said secondgear.

1. A tube cold rolling mill comprising a stand with rolls having avariable-section groove provided along a spiral line with a variableinclination angle along the groove length; a housing with guides forsaid stand made so as to ensure its reciprocalrolling motion relative tothe vertical axis; a drive with a crank mechanism for moving the standalong the guides of said housing; a linkage of said housing with thedrive of said stand made so that the angle formed by the guides of saidhousing and the axis of rolling is at each moment of time equal to saidvariable inclination angle of the roll groove; a crosshead, the housingof which is hinged to a crank mechanism of said stand drive and having acavity to accommodate a holder; said holder being disposed in saidcavity of the housing of said crosshead and able to turn relative to thevertical axis and having a hole for passing a billet and being hingedwith tie rods of said stand.
 2. A tube cold rolling mill as in claim 1,wherein said linkage of said housing with said stand drive is a crankmechanism comprising a connecting rod connected to said housing, a crankwheel connected to said connecting rod, a shaft having a fixedly mountedfirst gear linked to said crank wheel, a second gear fixedly mounted onsaid shaft, and a third gear on said drive of said stand and meshingwith said second gear.